The area of a transistor device within a differential amplifier circuit is normally minimized to reduce the effect of parasitic impedances such as collector-base capacitance C.sub.cb and collector-substrate capacitance C.sub.cs on the speed of the device. The larger these capacitances, the lower the bandwidth of the output signal. A smaller device, however, may not be optimally sized for the standing current density in the device. A mismatch of device area to current density lowers the transition frequency f.sub.T of the device from its maximum frequency and thus limits the device bandwidth. The standing current also determines the amount of load resistance and voltage swing that can be provided by the circuit. A number of tradeoffs therefore exist in the prior art among speed, bandwidth and maximum load of a device.
The present invention avoids these tradeoffs by neutralizing the effects of the parasitic capacitances. The device area can therefore be sized to accept the desired standing current whose density is chosen in response to the load resistance and projected voltage swing.